<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link href="https://cdn.bootcdn.net/ajax/libs/minireset.css/0.0.2/minireset.min.css" rel="stylesheet" />
  </head>
  <body>
    <style>
      .row {
        display: grid;
        grid-template-columns: repeat(12, 1fr);
        column-gap: 10px;
      }
      .col-6 {
        grid-column-end: span 6;
      }
      .col-3 {
        grid-column-end: span 3;
      }
      div > div {
        background-color: slateblue;
      }
    </style>
    <main class="container">
      <div class="row">
        <div class="col-6">1</div>
        <div class="col-6">2</div>
      </div>

      <div class="row">
        <div class="col-3">1</div>
        <div class="col-3">2</div>
        <div class="col-3">3</div>
        <div class="col-3">4</div>
      </div>

      <div class="row">
        <div class="col-3">8</div>
        <div class="col-3">2</div>
        <div class="col-3">2</div>
      </div>
    </main>
  </body>
</html>
